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Old 01-12-2006, 10:16 AM
Bruno_300TE Bruno_300TE is offline
Registered User
Join Date: Dec 2003
Location: Fribourg, Switzerland
Posts: 277

Many thanks to eveybody who shares his knowledge!
Yesterday I checked some stuff on the car:

(1) Duty cycle
  • Ignition on, engine off:
    30% constant reading on Fluke DMM (duty cycle 70%)
    ok, non californian car
  • Operating temp (idling and around 2500RPM):
    84-90% fluctuating (duty cycle 10-15%)
    base mixture too rich, oxygen sensor working
-> adjust base mixture to 50%. Surprisingly, I had to turn the adjustment screw on the fuel distributor (after I removed that anit-tapering tower) clockwise to get it around 50%. I thought this means richer? Confused here.
By the way, I replaced the oxygen sensor a week earlier, so I assume it is ok.
(2) EGR valve
Not sure that is a valid test for it: Applied pressure to the valve via the vacuum connection. The valve lost pressure quickly, suggesting it may not feel the vacuum that is required to operate it. Do I need a new valve?
(3) Ignition should be ok.
Coil, wires, distributor, rotor, spark plugs: all have been replaced in the last year.
(4) Vacuum.
The cubber hoses on the idle control valves are new. Also I replaced brittle vacuum lines and elbows where I saw them. What shall I check here, does anyone know a systematic way of doing it?
(5) Leak at the exhaust manifold/downpipe?
This is just an idea. When I installed the catalytic converter, I had a hard time fitting it. I had to grind etc. Finally I could not feel or smell any exhaust gases and the car ran quiet. But if there is air (oxygen) entering the downpipe it may fool the whole system. So I may apply some sealant paste to the manifold/downpipe junction.
Cam69ss, your numbers indeed look similar to mine. Is it correct that I have to go for a second test within 48 hours in MA? Or otherwise bring some paperwork with me from a shop with stamps and stuff to prove what repairs have been done to solve the problem? So I have to go to a shop if I do not apply for a retest within 48 hours?

Have a nice day! Bruno
1992 300TE 160 kmiles
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